Airplane engine

[UNSC MCPO]

I've got 5 little tiny airplane engines lying around here, and one of them has an adjustable throttle. It's called the ENYA 19-V Model 4005. I looked up specs and found out it has .38 BHP at 13000 RPM, which equates to .15 ft/lbs or 1.8 in/lbs. So with a 1:13 gear reduction, that means 23.4 in/lbs of torque at the wheels at 1000rpm! I would like to mount it to vex parts and have a neat dragster. Any ideas for what I should do would be appreciated. So far I've got:

Some sort of clutch so I can disengage to stop it without shutting off the engine. Thinking a normal friction clutch used on cars.

Tiny ball bearings, 13000 rpm is way too much for those plastic things.

Not sure if i should go with my own gear system, or will vex's high-strength gears be strong enough? Thinking a 1:13 ratio, so 1000rpm at the wheels. 5" wheels= about 21 ft/s.

Gear housing for safety. Kudos to gblake for that idea.

Please I don't want any comments telling me not to do this because its overkill or its blah blah blah. I don't care, I'm trying it no matter what you say.

[DinerKid]

i say you should mount a wheel to it and make a pitching machine.

[octanetripledax]

Just make a super high speed robot.

[UNSC MCPO]

not making a pitching machine

[gblake]

Please I don't want any comments telling me not to do this because its overkill or its blah blah blah. I don't care, I'm trying it no matter what you say.Just use the right parts for the right job and you won't hear those comments.

For example, when you are picking the shards of gears out of your eyes or flesh, use a sterile tweezer; and when you are dressing any wounds, use tape or other adhesives designed for that job, not duct tape. When the doctor dresses them properly later, you won't enjoy having duct tape removed.

I didn't follow how you jumped from 1.8 in-lbs at 13,000 RPM to 23.4 in-lbs at 1000 rpm. Can you supply a few more details on what you have in mind?

Blake

[UNSC MCPO]

Just use the right parts for the right job and you won't hear those comments.

For example, when you are picking the shards of gears out of your eyes or flesh, use a sterile tweezer; and when you are dressing any wounds, use tape or other adhesives designed for that job, not duct tape. When the doctor dresses them properly later, you won't enjoy having duct tape removed.

lol thats what i started this thread for

I didn't follow how you jumped from 1.8 in-lbs at 13,000 RPM to 23.4 in-lbs at 1000 rpm. Can you supply a few more details on what you have in mind?
(1.8)x(13)=23.4
1.8 in/lbs times 13 because of 1:13 ratio = 23.4 in/lbs
1/13th rpms, and 13 times the torque
i'm no physics expert, i could be doing something wrong there

[smartkid]

That is a neat idea! Good luck and post pictures when it's complete!

[UNSC MCPO]

how could i resist from posting pictures :D

[smartkid]

Yeah I know whatcha mean with the pictures. Video would be cool too.

[robofreak]

I think it all depends on how the mount on the front of the engine is. What I would try doing is getting the 12 tooth metal gears and stacking like 3 or 4 of those on the shaft of the nitro motor. (Securing them for such a high speed may be hard). These gears would drive 3 or 4 giant gears (like 84 teeth I think is the biggest). That is a huge gear ratio and should drop the rpm to a few thousand and from here a small gear ratio can drop it even lower to be under 1000rpm.

If you could post pictures of the engine that would be great.

However I do see a problem with using an airplane engine, at low rpm's they don't have much power and can be easily stalled so I think you would have to devise a clutch system to rev it up and then engaged the wheels. This makes me doubt that you can use these I mean no vex constructed component is going to be able to act as a clutch for a multi thousand rpm high torque engine. Vex was never designed to handle these rpm's and speeds which is asking for trouble, at 30mph the shaft collars will come undone and your robot will get messed up really bad after it crashes.

[UNSC MCPO]

The engine will always be at 13000 rpm unless I'm stopped and it's idling. I crunched some numbers, and found that a 1:5x1:5 will drop rpms down to 520, and 1:5x1:5x1:5 will drop to 104 rpms. The engine will hold the gear on with nothing but pressure, it's designed to hold propellers on that way, and the nut tightens with the force of it spinning. I'll post some pics in a minute.

[UNSC MCPO]

Bottom, mounting holes:http://www.vexforum.com/gallery/showimage.php?i=4061
Side:http://www.vexforum.com/gallery/showimage.php?i=4056&c=
Other Side:http://www.vexforum.com/gallery/showimage.php?i=4051&c=
Place where the first gear will be attached(12 tooth metal):http://www.vexforum.com/gallery/showimage.php?i=4046&c=

[whitepass]

A bit of realty is need here, one the fuel will dissolve most plastics, two the vibrations will tear your robot apart if you do not lock all screws, and three Vex shafts will not take that kind of torque. Oh and check your health insurance be for you start that motor in a Vex robot as you will need it!

[UNSC MCPO]

ok, so i'll make sure all fuel lines are not leaking.
all screws will be locked
why would a solid steel bar not take that torque?, it's not that much

[Vexer]

I can't seem to find the post but there was a thread titled "For those who say the Vex motors aren't powerful enough" that showed some seriously messed up axles from just the regular motors.

[whitepass]

forgot to tell you you will need to replace the cylinder head with one for use in RC cars, they have a much bigger heat-sink, or you could go water cooled but that would add a lot of wight. I have made several car-type steering robots and none of them would work at high speed, to much slop. Your best bet would be something like an air-boat with wheels. You should go talk to someone in a Hobby shop that has RC. Fuel will come out of the exhaust.

[robofreak]

I just don't see a point in putting this motor on the vex robot, if you can't devise a clutch system then really what is the point because the wheels would rotate constantly

BINGO I just had an idea, if you can hook up this motor and gear it to an axle like you were talking about then you could use a third wheel with an electric motor to prop the drive wheels off the ground. Then you would just reverse the motor and the prop would raise up and the drive wheels would touch the ground. This is the only way that I can see it working as a stop and go robot.


If you get this to work then make a full youtube video of it, I would love to see a nitro engine on a vex chassis :D :D :eek: :D

[gblake]

I just don't see a point in putting this motor on the vex robot, if you can't devise a clutch system then really what is the point because the wheels would rotate constantly

BINGO I just had an idea, ...And your idea just gave me one - Many industrial machines use high-efficiency fossil fuel motors to generate electricity, and then use the electricity to carry out the machine's real purpose. This decouples the fossil fuel engine from much of the variablity in the machine's operating environment.

If you hook your airplane engine up to many types of electric motors, you can use them to generate electricity rather than consume it....

Blake
PS: Don't forget the previous admonitions about using sterile tweezers to pluck pieces of shrapnel out of observers, and about avoiding using duct tape to dress a wound.

[UNSC MCPO]

I'm thinking I'll just simply make a high torque robot, with front wheel steering and rear wheel differential drive. Anyone know of any custom gearboxes to suit my needs?

[DinerKid]

And your idea just gave me one - Many industrial machines use high-efficiency fossil fuel motors to generate electricity, and then use the electricity to carry out the machine's real purpose. This decouples the fossil fuel engine from much of the variablity in the machine's operating environment.

If you hook your airplane engine up to many types of electric motors, you can use them to generate electricity rather than consume it....

Blake
PS: Don't forget the previous admonitions about using sterile tweezers to pluck pieces of shrapnel out of observers, and about avoiding using duct tape to dress a wound.

i like this idea a lot.l i am currently making a decent sized wind turbine for my house. this seems like an awesome project you could make your own alternator with magnet wire and spin up some magnet rotors with the airplane engine and charge up some batteries to run a bot. way cooler way more safe. this takes my vote.

[robofreak]

I'm thinking I'll just simply make a high torque robot, with front wheel steering and rear wheel differential drive. Anyone know of any custom gearboxes to suit my needs?

Nope, I don't know of any gearboxes that would do this for a reasonable price. The only way you could gear it would be to make a custom vex gearbox. You could build an external gearbox for vex by making a square bot cube in which every gear and the motor is mounted with an output shaft for hooking it up to a bigger bot.

As for converting the motor into electrical energy, this is possible but you lose energy in the conversion between the two. Its doable though check out the hybrid robot, it has the capability to generate over a kilowatt onboard

http://www.engadget.com/2007/09/23/hybrid-robot-runs-on-gasoline/

[gblake]

...As for converting the motor into electrical energy, this is possible but you lose energy in the conversion between the two. Its doable though check out the hybrid robot, it has the capability to generate over a kilowatt onboard

http://www.engadget.com/2007/09/23/hybrid-robot-runs-on-gasoline/Sure you lose energy - But that doesn't keep it from being an excellent method for building the power plants for locomotives, warships, other home construction tools, and other nifty gadgets. - You gain many advantages.

Blake

[fryfrog]

Instead of using vex parts to drop the rpms down to a reasonable level, why not buy something from the RC world that already does this? You'd get a clutch and rpm reduction all in one package.

That said, I've used my fair share of small nitro and gas r/c engines and I would *not* put one into a vex robot for a wide variety of reasons.

1) The high rpms and combustion engine nature of the thing means tons of vibration. This has already been mentioned a couple times, but you'll have to lock down *everything* on your robot or it will just shake itself apart. Probably even want some rubber isolation mounts for the engine to make it even better.

2) They are very, very finicky. They can be hard to start, hard to keep idling and hard to get nicely tuned. After having 2-3 nitro boats, I can honestly say I will never buy a nitro engine based RC anything. I much prefer a simple gas 2 stroke engine, as unreliable as they are... they are far better than a nitro engine.

3) They are *very* messy. As someone already mentioned, the fuel is not just fuel. It is also lubricant *and* coolant. So it sprays out a ton of messy, terrible stuff along with the exhaust.

4) Did anyone mention load as blazes? Oh, and the fuel is like $20/gallon as well.

5) Can't forget safety either. Everyone has mentioned your 13,000 rpm engine spinning stuff so fast that it flys apart and wings you in the eye... but a big hunk of metal going 20 or 30 miles an hour (what is the math on 1000rpm to even the small wheels?) is going to do some damage to something or someone when you lose control. And you will lose control, be it through radio failure, mechanical failure or human failure.

If you want fast, w/o the mess... I think I'd adapt an electric rc motor with a speed controller and transmission.